Electrical power is delivered from power generation facilities (i.e. power plants) to consumers by a system of transmission lines and transmission facilities referred to as a power grid. Power generation facilities generate electrical power at a near constant rate. Demand for electrical power, however, fluctuates. To address this issue, power storage facilities are connected to the power grid. During times at which the amount of electrical power that is generated exceeds the amount of electrical power that is consumed, power is stored by the power storage facilities. The power storage facilities return power to the power grid during times at which the demand for electrical power exceeds the amount being generated. Many different systems are used to store electrical power, including systems that store power by pumping water, compressing gases, charging batteries, and spinning flywheels.
Currently, electric vehicles are becoming common. Electric vehicles commonly include battery packs that are charged when the vehicle is not in use. Vehicles are commonly parked most of the time, and in the case of electric vehicles, the vehicle is connected to a charging system for much of the time it is parked. Vehicle-to-grid systems intend to take advantage of this situation by utilizing the batteries of electric vehicles for grid power storage, operating in a manner similar to traditional power storage facilities. Thus, in a vehicle to grid system, charging is managed, to the extent practical, such that charging occurs primarily when overall demand for electrical power from the grid is low. During peak demand times, electrical power can be returned to the grid from the batteries of the electric vehicle. Power losses can, however, occur during return of electrical power to the grid from the batteries of the electric vehicle, which diminishes the benefits of participation in the vehicle-to-grid system by the electric vehicle.